Instituto de Salud Carlos III, Majadahonda, Spain.
Clin Microbiol Infect. 2013 Jun;19(6):E271-7. doi: 10.1111/1469-0691.12110. Epub 2013 Mar 7.
The performance of a pan-fungal PCR-based technique was evaluated to assess the aetiology of invasive fungal diseases (IFDs). A total of 89 formalin-fixed paraffin-embedded biopsy samples from 84 patients with proven IFD were studied. Culture of tissue was performed in 68 (81%) patients. The sensitivities of the PCR-based technique and microbiological culture of tissues were 89% and 56%, respectively (p <0.01). According to PCR results, Aspergillus species accounted for 67%, Candida species for 13%, zygomycetes for 11%, and rare and emerging fungi for 9%. Aspergillus species were significantly associated with lung samples (79.6%, p <0.01), Mucorales were associated with skin/subcutaneous samples, and Candida species were associated with gastrointestinal samples. Regarding biopsy samples with Aspergillus species, Aspergillus fumigatus DNA was detected in 43 of 50 (86%), and Aspergillus flavus in six of 50 (12%). PCR was positive in 24 of 30 (80%) cases with negative culture. In nine of the 84 patients, the PCR technique failed to amplify the DNA. Six also had negative cultures, and in the remaining three cases culture was positive (Rhizopus microsporus, Rhizopus arrhizus, and Sakseneae vasiformis), suggesting that the PCR technique was not as effective in amplifying the DNA of some species of Zygomycetes. In five cases, there was no correlation between culture results and those obtained with DNA amplification, indicating the possibility of a mixed infection or the presence of colonizer/contaminant microorganisms. In summary, PCR-based techniques for DNA amplification should be implemented in histopathology and microbiology departments, as they appear to be complementary to conventional methods for IFD detection.
本研究旨在评估一种基于真菌通用 PCR 技术的检测方法，以评估侵袭性真菌病（IFD）的病因。共对 84 例确诊 IFD 患者的 89 份福尔马林固定石蜡包埋活检样本进行了研究。对 68 例（81%）患者的组织进行了培养。基于 PCR 的技术和组织微生物培养的敏感性分别为 89%和 56%（p<0.01）。根据 PCR 结果，曲霉菌属占 67%，假丝酵母菌属占 13%，接合菌纲占 11%，稀有和新兴真菌占 9%。曲霉菌属与肺部样本显著相关（79.6%，p<0.01），毛霉目与皮肤/皮下样本相关，假丝酵母菌属与胃肠道样本相关。对于有曲霉菌属的活检样本，50 例中有 43 例（86%）检测到烟曲霉 DNA，50 例中有 6 例（12%）检测到黄曲霉 DNA。24 例培养阴性的病例 PCR 为阳性。84 例患者中有 9 例 PCR 技术未能扩增 DNA。其中 6 例培养也为阴性，其余 3 例培养阳性（少根根霉、结囊地霉和匐枝根霉），这表明 PCR 技术在扩增某些接合菌属真菌的 DNA 方面效果不佳。在 5 例中，培养结果与 DNA 扩增结果之间没有相关性，表明可能存在混合感染或定植/污染微生物的存在。总之，基于 PCR 的 DNA 扩增技术应在组织病理学和微生物学部门实施，因为它们似乎与 IFD 检测的常规方法互补。
